body, html, main {
 /* important */
 height: 100%;
}
 
.cd-fixed-bg {
 min-height: 100%;
 background-size: cover;
 background-attachment: fixed;
 background-repeat: no-repeat;
 background-position: center center;
}
 
.cd-fixed-bg.cd-bg-1 {
 background-image: url(../img/1080p.jpg);
}
.cd-fixed-bg.cd-bg-2 {
 background-image: url(../img/1080p.jpg);
}
.cd-fixed-bg.cd-bg-3 {
 background-image: urlurl(../img/1080p.jpg);
}
.cd-fixed-bg.cd-bg-4 {
 background-image: urlurl(../img/1080p.jpg);
}
 
.cd-scrolling-bg {
 min-height: 100%;
}